Horizontally expandable, silage storage bags are commonly used as an alternative to permanent feed storage structures such as barns and silos. From an economic standpoint, the expandable storage bag is preferable to more elaborate, permanent structure. Further, the expandable bags are more easily loaded than permanent structure and the silage stored therein is readily accessible for use.
An exemplary prior art structure is disclosed in Reissue U.S. Pat. No. 31,810, to Lee. A tractor-powered loading apparatus is disclosed in association with an expandable bag. A backstop is located at the filled end of the bag and has attached thereto laterally spaced cables which extend back to rotatable cable drums. The drums are yieldably braked and, under a predetermined force applied to the cables, release the cable to allow movement of the loading apparatus and tractor away from the filled end of the bag. The bag is filled by a toothed rotor which propels silage through a short tunnel and into the bag inlet. By presetting the braking structure to yield at a desired cable tension, an operator can select the degree of compaction of silage in the bag.
The bag in such bagging machines is manufactured and delivered in a pleated shape, i.e., folded into an accordion-bellows-type shape. Typically, a bag having a nominal ten-foot-diameter (approximately 3 meters diameter, or 9.6 meters circumference) and a 300 foot length (approximately 90 meters length) will be folded to a 10-foot-diameter (about 3 meter) ring about 1 foot (about 0.3 meter) long and 1 foot (about 0.3 meter) thick. To start the loading operation, this bag-ring is pre-loaded around the tunnel, and the pleats are unfolded one at a time as the bag is deployed and filled with feed stock.
In U.S. Pat. No. 4,688,480 issued Aug. 25, 1987 to Ryan, an agricultural feed bagger is described. A brake disk on a shaft associated with spaced cable feeding drums that are yieldably braked controls compacting of the feed and the expansion of the bag. Prior-art FIGS. 1A (plan view), 1B (elevation view), 1C (front perspective view, showing bag 99 being filled) and 1D (back view) illustrate one such feed bagging machine 100. Tractor 91 provides power to the feed bagger 100, but does not pull the bagger 100, rather, the pressure from the feed filling the bag pushes the bagger 100 and tractor 91 ahead at a rate equal to the filling of bag 99. A steel cable between bagger 100 and backstop 101 is yieldably held by a disk-brake mechanism 141 that ensures the feed is compacted before the bagger is allowed to advance. A rotor 130 having multiple teeth 131, and powered by a power-take-off (PTO) shaft 133 from tractor 91, forces feed 98 up and back into a short tunnel 150. Movable upper bag bracket 125 is used to lift the folded bag into place on the outside of tunnel 150, and supports/holds the folded bag 99 at the front end of the top of tunnel 150 as it unfolds from the inside. Lower bag tray 120 is substantially horizontal, supported at a fixed level at its front edge by brackets 121, and yieldably supported at its back edge by spring-and-chain 124 (which can have its force adjusted by setting various chain links of the chain onto a fixed hook at the top). Elevator 140, which has a cleated moving belt 141 (e.g., a cleated rubber belt or a chained flight conveyer) moves feed up between two side walls 142 that are substantially vertical at the top of elevator 140. The feed then drops into hopper 139. Such a bagger 100 has a tunnel 150 that provides some support for bag 99 as it unfolds, but which has side walls along which the bag unfolds that are substantially parallel to the direction of travel of the bagger 100. The bagger itself provides negligible back-pressure to the feed which thus presses the bag outward once the feed reaches the bag into a cross section that is circular/oval initially. FIG. 1E is a cross-section view of section 1E--1E from FIG. 1B showing the general oval-like shape 89 of bag 99 after the bag 99 has being filled and passed beyond tunnel 150, (with a flat bottom against the ground, but which collapses more over time (e.g., several days or weeks) to shape 89').
U.S. Pat. No. 5,355,659 describes a tunnel that can be lengthened, for example by a hydraulic cylinder.
U.S. Pat. No. 5,517,806 describes a tunnel that has ridges on the inside vertical surfaces. It also describes cables that cross in the feed path in the bag.
U.S. Pat. No. 5,355,659 describes a tunnel that includes horizontal cables in the feed path in the bag.
There are numerous problems that one contends with using such previous bagging structures. To a large degree, the compliance of the bag itself, combined with the force provided by the teeth pushing feed into the bag against the pressure provided by the compliance of the plastic bag and the braking structure determines the amount of compaction of the feed. That is, to a large extent, the compaction of the feed takes place in the bag itself. As the bag deploys, folds in the bag release unevenly, and the varying pressure of feed against the stretchable plastic bag varies the compaction at various points along the length of the bag, leaving a lumpy bag and often leaves pockets of air. This air allows decomposition or spoilage of the feed in the bag, and a resulting loss of nutritional value remaining for the livestock that eat the feed. In addition, the degree of compaction varies with varying moisture/dryness in the feed, the type of feed (e.g., corn silage vs. hay silage vs. grains, etc.).
What is needed is a apparatus and method for bagging agricultural feed that provides a high amount of even compaction in varying conditions.